The Seismic Response Analysis Of Cable-stayed Bridge Based On The Random Vibration Theory

Since the beginning of the twenty-first century, the activities of the Earth’s interior was particularly active, a variety of earthquake disaster has brought huge losses to human life and property, traffic engineering, as the economic ties that connect the various regions, once destroyed will lead incalculable influence directly to the people of various economic activities and life. The most talked about in the traffic engineering is the bridge, the bridge across the valley, the river,earthquake damage was a small impact on traffic to travel, a big impact to cut off the channels of the earthquake zone to promote this life disasters aggravated. In the ranks of the bridge, cable-stayed bridge with its span, the novel structure and perfect visual effects and giving people a profound influence, occupy a pivotal role in the development of the transport. How to ensure that large span cable-stayed bridge during construction and operation have sufficient seismic safety has become a major issue in front of the bridge design and research workers in this earthquake-prone countries.Bridge seismic theory experienced from the static method, response spectrum method, the dynamic time-history analysis, the evolution of the random vibration method. in the seismic analysis of large span cable-stayed bridge, due to the large deformation behavior of the structure, the spatial variation of the structure of the seat of inconsistency and randomness of the seismic input, it makes the bridge seismic research become complex and difficult. In large span cable-stayed bridge, seismic research process, we need to take into account many factors, summarizing the pros and cons of various methods, to get the correct answer in the seismic analysis of the structure.In this paper, as a760m span cable-stayed bridge in Inner Mongolia the object of study, it summed up bridge seismic response analysis theory on the basis of the previous theoretical study of bridge seismic design, while using the general-purpose finite element software ANSYS platform dynamic analysis and random vibration theory, analyzed the bridge dynamic response characteristics, in order to be the performance evaluation and reference to the bridge seismic, this paper includes the following: Firstly,it detailed the basic theories and methods of bridge seismic design, including the static method, the response spectrum method, dynamic time-history analysis and random vibration analysis, and explored the characteristics of the various methods of analysis.Secondly, with structural analysis program ANSYS,it established Little Haven Yellow River Bridge, space truss finite element model, detailedly analyzed the process of the entire model.Again,it respectively analyzed the modal of cable-stayed bridge modal under the conditions of linear and nonlinear,access to the bridge model, the natural frequencies and mode shapes,compared the impact of the frequency of access to structural of modal under the vibration characteristics of linear and nonlinear,laid the foundation for the subsequent transient dynamics.Fourthly, it described the general steps of the ANSYS transient structural analysis. In view of the flexible features of the cable-stayed bridge,considered the impact of the geometrically nonlinear,analyzed the dynamic time history analysis of the structure,with incentives directly on the structure of the input.it summarized of the input modes and methods in different analytical category fields;it investigated the structure inspired by one-dimensional, two-dimensional and three-dimensional vibration response with geometry nonlinear, comparing to the dynamic linear conditions.Fifthly, it discussed the affect of traveling-wave to response analysis of the structure, which is generated by the time difference in the basis of cable-stayed bridge in the communication process.Sixthly, it summarized the previous established spectral density, investigated the characteristics of each model.Learned from the scholars parameters, this parameter as a random vibration input to provide the basis for follow-up random seismic response analysis. based on Probability and statistics theory and vibration theory, preliminary analyzed the dynamic statistics response of the structure under uniform excitation of stationary random earthquake.Finally, it summarized of this study and also pointed out the problems to be solved by further study.